Conventional transmission selector rod assemblies include a transmission selector rod which extends through a seal into a housing. The seal conventionally comprises a rubber boot covering a portion of the rod and the housing. While such a structure performs its desired sealing function, it is relatively heavy, requires a secondary attachment, and is not readily installed and lends itself to failure due to cracking and pull-off from the housing. Conventional transmission selector rod assemblies also include a switch attached to the housing and associated with the selector rod to effect electrical control of a particular electrical component (e.g. a lean burn system) of the motor vehicle with which the transmission selector rod assembly is associated. The switch is relatively expensive, and adds further weight to the system, and requires additional assembly.
According to the present invention, it is possible to provide a seal for a transmission selector rod that overcomes the disadvantages associated with conventional structures, as recited above. According to the present invention, it is possible to reduce the weight and size of the transmission selector rod housing assembly, provide a seal that is self contained and easily installed, and one that does not require a secondary attachment, could replace a bearing that otherwise would be molded into the housing unit, and to eliminate the switch commonly associated with the transmission selector rod assembly. These advantageous results are accomplished according to the present invention while an excellent seal is still provided, which seal prevents foreign material from entering the housing.
According to one aspect of the present invention, a transmission selector rod assembly is provided. The assembly includes the conventional components of a housing and means defining an opening into the housing for receipt of a transmission selector rod, to allow the selector rod to move back-and-forth with respect to the housing. According to the present invention the means for providing a seal at the opening to engage the selector rod and seal the housing from the surrounding environment includes a pile fabric strip having at least some electrically conductive fibers, and means for mounting the fabric strip surrounding the opening so that the pile (including at least some electrically conductive fibers) extends radially inwardly from a position surrounding the opening to engage the selector rod when received within the opening. According to the present invention the assembly further comprises an electrical conductor electrically connected to the fabric strip and extending away from the housing, to provide an electric circuit with the fabric strip and an accessory electrical component (such as a lean burn system). The metal transmission selector rod has a plurality of spaced electrically nonconductive portions formed on the surface thereof, while the fabric strip may have the electrically conductive fibers thereof formed in a section with a predetermined width, the nonconductive portions formed on the surface of the selector rod having a width slightly greater than the width of the section of conductive fibers. Such an arrangement effects the switching conventionally provided by the switch, and allows elimination of that structure without consequent loss of the switching function.
The fabric strip for providing the seal according to the present invention preferably includes a number of different sections. A first section including a resilient fiber pile, and a third similar section, are disposed on either side of a second section including a low-friction fiber pile. Backings may be provided for all or some of the various section fiber piles, and the backings may be received by one or more recesses formed in the housing in communication with the opening. The second section serves as a bearing strip in the housing. In this way a proper seal is provided while resistance to the back-and-forth movement of the transmission selector rod is minimized. A fourth section of electrically conductive fibers may be disposed between the second and third sections.
The fibers forming the fabric strip may be chosen from a wide variety of conventional fabrics. In this regard, the term "pile" as used in the present specification and claims is used in its broadest sense, covering cut or uncut loops in general which make up the surface of a pile fabric. The fibers of the resilient fiber pile may comprise silicone wool, natural wool, or other fibers having resilient properties similar to silicone and natural wool. The fibers of the low-friction fiber pile are preferably polytetrafluoroethylene fibers, although a wide variety of other fibers having friction properties similar to polytetrafluoroethylene may be provided. All sections may be provided as a blend of different fibers rather than being homogeneous. For the backed sections, the backing preferably is provided by polypropylene. Polypropylene fibers are preferably provided in such backed sections to provide compatibility with the backing. The electrically conductive fibers may include stainless steel fibers. The woven fabric strip combining all the sections may have the plan configuration of a parallelogram for ease of wrapping and installation.
The preferred fabric strip according to the present invention is eminently suited for use in the transmission selector rod assembly. However, the fabric is not restricted to that use, and can be utilized in other environments where similar properties are desirable.
It is the primary object of the present invention to provide an advantageous sealing arrangement. This and other objects of the invention will become clear from an inspection of the detailed description of the invention, and from the appended claims.